From 063acaca15e8a6a3e9dcd3ed11fd0a4a5cfd17ed Mon Sep 17 00:00:00 2001
From: Peter Mosses <18308236+pdmosses@users.noreply.github.com>
Date: Sun, 30 Oct 2022 21:19:47 +0100
Subject: [PATCH] Fix top-level active link (#1015)
* Fix top-level active link
Fixes #1014
1. Reverse the order of `page.parent == node.title or page.grand_parent == node.title`. This makes no difference.
2. Replace `page.parent == node.title` by `page.parent == node.title and page.grand_parent == nil`. The condition is evaluated first because it is rightmost.
We have `node in first_level_pages`.
The old condition holds not only when `page` is a child of `node`,
but also when `page` is a grandchild of a *different* top-level page and its parent happens to have the same title as `node`.
The new condition never holds for a grandchild.
This change has been tested locally: in v0.4.0.rc3, when the 3rd-level page `G` was selected, the link to the top-level page `F` was active, and the link to its child `G` was shown; after making the change, it is no longer active, so the link to its child `G` is not shown.
* Update nav.html
Add a comment to clarify just when top-level nodes are active.
---
_includes/nav.html | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/_includes/nav.html b/_includes/nav.html
index c3d6782d..305ac715 100644
--- a/_includes/nav.html
+++ b/_includes/nav.html
@@ -130,12 +130,36 @@
{%- comment -%}
The order of sibling pages in `pages_list` determines the order of display of
links to them in lists of navigation links and in auto-generated TOCs.
+
+ Note that Liquid evaluates conditions from right to left (and it does not allow
+ the use of parentheses). Some conditions are not so easy to express clearly...
+
+ For example, consider the following condition:
+
+ C: page.collection = = include.key and
+ page.url = = node.url or
+ page.grand_parent = = node.title or
+ page.parent = = node.title and
+ page.grand_parent = = nil
+
+ Here, `node` is a first-level page. The last part of the condition
+ -- namely: `page.parent = = node.title and page.grand_parent = = nil` --
+ is evaluated first; it holds if and only if `page` is a child of `node`.
+
+ The condition `page.grand_parent = = node.title or ...` holds when
+ `page` is a grandchild of node, OR `...` holds.
+
+ The condition `page.url = = node.url or ...` holds when
+ `page` is `node`, OR `...` holds.
+
+ The condition C: `page.collection = = include.key and ...` holds when we are
+ generating the nav links for a collection that includes `page`, AND `...` holds.
{%- endcomment -%}
<ul class="nav-list">
{%- for node in first_level_pages -%}
{%- unless node.nav_exclude -%}
- <li class="nav-list-item{% if page.collection == include.key and page.url == node.url or page.parent == node.title or page.grand_parent == node.title %} active{% endif %}">
+ <li class="nav-list-item{% if page.collection == include.key and page.url == node.url or page.grand_parent == node.title or page.parent == node.title and page.grand_parent == nil %} active{% endif %}">
{%- if node.has_children -%}
<a href="#" class="nav-list-expander" aria-label="toggle links in {{ node.title }} category">
<svg viewBox="0 0 24 24"><use xlink:href="#svg-arrow-right"></use></svg>
--
GitLab